Long chain alkyl substituted 4-amino-1, 8-naphthalic acid imides



Patented Sept. 18, 1945 2,385,106 LONG CHAIN ALKYiJ SUBSTITUTED '4- ANIINO-LS-NAPHTHALIC ACID HVIIDE'S f .Mario Scalera, Somervillc, and Asa 'Willard Joyce,

Plainfield, N. J., assignors to American Cyanamid Company, New York, N. Y., a corporation of Maine 'No Drawing. Application September 5, 1942, Serial No. 457,517

Claims. (or. 260-281) This invention relates to'new oil-soluble yellow dyes derived from '4-amino-1,8-'naphthalic acid imides. I

It has been roposed to prepare derivatives of 4-amino-1,8-naphthalic acid in'which both nitrogen atoms are replaced by the same alkyl radical.

According to the present invention we have found that, in order to obtain high solubility in mineral oil, combined with high fluorescent strength, it is important to have a single long chain alkyl radical in the molecule.

If dyes are prepared in which the 4-amino group is substituted by an aliphatic hydrocarbon of at least 12 carbon atomsy-while'the imide group is substituted by an alkyl radical of less than 6 carbon atoms, high oil solubility is obtained and it is possible to use these dyes to impart to lubricating oil a fluorescence. The new dyes fluoresce very strongly and when dissolved in lubricating oils improve their appearance. The dyes are also useful in coloring plastics which are to fluoresce under ultraviolet light,

The dyes of the present invention may be represented by the following formula:

N-Alk in which one of the groups, Alk and Alkl, is an aliphatic hydrocarbon radical having at least 12 carbon atoms and the other lower alkyl group having less than 6 carbon atoms.

The compounds of the present invention are not limited to any particular method of preparation, but we prefer to produce them by a two step process in which a 4-bromo or 4-chloro-1,8- naphthalic anhydride is first condensed with the desired aliphatic amine under conditions such that the amine reacts only with the anhydride group. It is notdifficult to limit the reaction of the amine to'the anhydride group as this group is much more reactive than is'the halogen, and if an approximatelytheoretical amount 'of amine is brought into the reaction, preferably 'in an inert diluent, only the anhydride groups react. The resulting product can then be reacted 'with the other primary alkylamine, the reaction bein preferably carried out in the presence of a cupriferous catalyst and a substance capable of amine, the proper catalyst, and the acid binding substance.

The temperature in-the=flrst step is not critical and can be maintained at a moderate tempera- 6 ture, preferably below 150 C.,.but the second step is more easily carried out at higher temperatures, for example 150-225" 'C. and canbe carried out at atmospheric pressure if the second amine is the long chain one. These are the preferred productsn i "Either the .4-brom naphthalio anhydride .or the 4-chlornaphthalic anhydride maybe used,fbut as the bromo compoundis considerably-more active, it'i preferred. a 1 i Thenatureof the cupriferous catalystand acid binding substance isnot critical and the common cupriferous catalysts such as copper powder, cupric chloride, cuprous chloride, cuprous iodide or mixtures of copper powder and iodine may be used. Alkali metal carbonates or acetates form very effective acid binding agents andare pree ferred although any other suitable acid'bindingagent may be used.

The new compounds are yellow dyestuffs, very soluble in paraifin hydrocarbons and in many organic plastics and capable of producing greenishyellow colors by reflected light and yellow colors by transmitted light. They all fluoresce a very intense green when exposed to ultraviolet radia- 30 tion. The high solubility in aliphatic hydrocarbons renders the dyes very useful for dyeing gasoline or lubricating oil. They may also be used in dyeing a wide range of plastics such as methacrylates, polystyrenes, nitrocellulose, cellulose =ac'etate and the likeand are suitable for producing colored plasticarticles which are to be used under circumstances where fluorescence is desirable such as for example in-black-outs, tinmotion picture theaters and the like; Another "fleldoffuse is-in 40 the'dyeing ofwax, particularly'for candles, beautiful canary yellow shades being'obtainable which fluoresce yellow and yel1ow-green:'under ultraviolet light. a V 4,5 The invention will be illustrated in greater deamples. The parts are by wei ght.

Example 1 N-CHzCHzGHzCH:

55.4 parts '4-abromo LB-naphthalic anhydride (M. P. 2l8-9 .C.) is intl'oduce'd'in'to 455' p'arts 9- dichlorobenzeneyth'e mixtureis stirred and heated to 13540 G. 16i0 parts nbutylamine is now 60 added gradually over'theicourse offilhours. After il in conjunction with the following typicalex perature of the reaction mixture to 160-65 C.

The charge is cooled to 100 C. and 2.0 parts sodi um carbonate are added, whereuponthemixture ing, the crude 4-bromo1,8-naphthalic N-butylimide crystallizes as a pale yellow substancewhich r 5 after recrystallization from alcohol shows the melting point of 104105 C.

Example 2 100 parts 4 -bromo-1,8-naphthalic anhydride (M. P. 218-9? 0.) is introducedinto 260 parts odichlorobenzene. the charge is stirred and heated to 135-40 C. Then 40 parts commercial amylamine are added gradually during the courseof 2 hours, water and excess amylamine refluxing. After heating for 2-3 hours. longer at 135-40 C. the water and excess amylamine areremoved by distilling and raising the temperature of the reaction mixture to 160-65 C. v On cooling to room temperature there is no separation ofithe reaction product. To isolate'it lofdichlorobenzene is. removed by steaming. Aviscous'yellow' liquid re mains which solidifies on 'cooling. The yield is nearly theoretic'al. Qn recrystallization from 'alcohol the 4-bromo-1,8-naphthalie N-amylamide is obtained i pale yellow crystals melting at 73- "75 C.

125 parts 4-bromo -1,8-naphthalic-N-amylim-' ide; 100 parts octadecylamine, 2.25 parts copper powder and 21.2 parts sodium carbonate are introduced into 260 parts o-dichlorobenzene." The mixture is stirred "and hea'ted to a temperature of 16570 C.'for 15 hours. The deep yellow reaction mixture is cooled to90-100 C. and filteredfrom insoluble inorganic matter which may bewashed with a further quantity ofdichlorobenzene. The filtrate is now steamed to remove solvent and-a dark brownish-yellow thick oilg'insoluble in water, remains. On cooling this forms a soft waxy mass, from which the accompanying water may be separated. Yield of crude product is approximately theoretical.

Instead of starting wiht isolated 4-bromo-1,8- naphthalic N-amylimide, V the dichlorobenzene solution as is obtained accordingto Example 2, may be used directly, the amounts of octadecylamine, copper and sodium carbonate and the other conditions remaining the same.

The 4-octadecylamino-1,8-naphthalic acid-N- amylimide is readily soluble in cold hexane, and in higher paraifin hydrocarbons such as mineral oil. It is also soluble in cold benzene, carbon tetrachloride, acetone, and alcohol. A solution in mineral oil does not crystallize.

5. is steamed to remove vdichlorobenzene. 0h. cool- Very' dilute. solutions (l:10;000-1:30,000) in mineral oil exhibit a bright greenish fluorescence. More concentrated solutions are yellow by trans "mitted light.

" Example 4 N-CHzCHzOHzCHa Theprocedure of Example 3 is followed except that insteadof the 4-bromo-1,8-N-amylnaphthalim ide, the corresponding n-butyl compound is used.. A dyestuff is produced in good yields and has substantially the same properties as those of I the product of Example 3.

Example 5 NC5H11:

The procedure of Example 3 was followed but a technical mixture of hexadecyl and octadecylamine is employed. The ;resulting product is of substantially the same color and properties.

Example 6 III uHu H 12.7 parts 4-bromo-1,8-naphthalic-N-amylimide, 7.4 parts dodecylamine 2.1 parts dry sodaash', 0.22 parts copper powder and 0.22 parts iodine crystals are introduced into 32.5 parts 0- dichlorobenzene and the mixture is stirred and heated tofa temperature of 70 C. for 10 hours. "After cooling to' 90-100" C. the reaction mixture is filtered to remove insoluble metallic compounds, and then steamed to remove odichlorobenzene. The residual oil, insoluble in Water 'is yellow, and forms a semi-solid waxy mass on cooling. It is readily soluble in toluene, carbon tetrachloride, acetone, alcohol, benzene, somewhat less soluble in paraflin hydrocarbons. The r 4-dodecylamino- 1,8-naphthalic-N -amyli1nide separates from hexane in beautiful greenishyellowcrystals, melting at90-92 C. exhibiting an intense yellowish-green fluorescence in solid form. Its dilute solutions in organic solvents alsoexhibit an intense'fluorescence.

Example 7 N-CnHza 8.3 parts 4-bromo-L3-naphthalic anhydride and 6.0 parts dodecylamine (95%) are introduced into 24 parts monochlorobenzene. The mixture is stirred and heated to reflux temperature (117-120 C.) for 5 hours. The solvent is removed by steaming, and on cooling a soft waxy mass, insoluble in water, is obtained. Recrystallized from acetone, the 4-bromo-1,8-naphthalic- N -dodecylimide shows a M. P. of 55-58 C. and is a white crystalline substance soluble in benzene, alcohol and acetone.

Example 8 N-GuHu amylamino-1,8-naphthalic acid-N-dodecylimide, 4

is obtained as a viscous yellow liquid exhibiting a strong greenish fluorescence in hydrocarbon solvents.

We claim: 1. New compounds of the formula:

Ni-Alk o=c o=o N-Alk in which one of the groups, Alk and Alkl, is an aliphatic hydrocarbon radical having at least 12 carbon atoms and the other is an alkyl radical having less than 6 carbon atoms.

2. New compounds of the formula:

N C5H2n+1 0= 0:0

III-A11; H

15 in which Alk is an aliphatic hydrocarbon radical having at least 12 carbon atoms and n is a whole number less than 6.

3. A 4-ootadecylamino-1,8-naphthalic acid-N- amyl imide having the following formula:

4. A 4-hexadecylamino-1,8-naphtha1ic acid-N- amyl imide having the following formula:

III-C 15112: H

5. A 4-octadecylamino-1,8-naphthalic acid-N- butylimide having the following formula:

N-C4Ho bf-CzsHn H M. SCALERA ASA WILLARD JOYCE. 

